IRON. 



403 



brown iron ore. Lustre silky. Adheres to the tongue. Soft. Sectile. Specific gravity 

 2.336 [Richardson). Before the blowpipe on charcoal, it decrepitates, and assumes a dark 

 red brown colour, but does not melt ; with borax, it fuses readily into a dark red coloured 

 bead. Heated alone in a glass tube,' it gives off water, and the colour changes to a dark brown. 

 Composition. Phosphoric acid 17.86, peroxide of iron 36.32, silica 8.90, alumina 10.01, 

 lime 0.15, water and fluoric acid 25.95 {Stemmann). Phosphoric acid 20.50, peroxide of 

 iron 43.10, silica 2.10, lime 1.10, magnesia 0.90, water 30,20, oxide of manganese a 

 trace {Richardson). 



Geological Situation. This mineral was first found at Urbeck in Bohemia, associated 

 with clay ironstone, which occurs in the coal formation. It has also been found with specular 

 iron ore, in the Potsdam sandstone. 



localities. 



Cacoxenite has been found in considerable abundance, accompanying the specular iron ore 

 and crystallized quartz, at the Sterling iron mine in the town of Antwerp, Jefferson county. 

 The mineral occurs here in minute radiated tufts or stars made up of leaves or fibres, which 

 somewhat resemble iron pyrites. The colour, when recently exposed, is yellow ; but the 

 surface becomes brovra, and somewhat pulverulent, on exposure. The lustre of the blades 

 is silky, or approaching to metallic. Alone before the blowpipe, it is infusible, but becomes 

 of a darker colour, and is attracted by the magnet. In this respect it differs from karphohte, 

 which is said to be fusible. 



Inferior specimens of this mineral are also found associated with red oxide of iron, on 

 Mount Defiance, near Ticonderoga, Essex county. 



Prof. Shepard suggests that this mineral is a mere variety of Wavellite, and Beudant intro- 

 duces it as an appendix to his Klaprothine, the Azurite of Phillips ; but it seems to me to be 

 quite distinct from both those species. 



ILVAITE. 



[From the island of Elba, where it was first found.] 



Fer Calcareo-Siliceux. HnHy. — Yenite. Ckaveland, PkiUips and Shepard. — Ilvaite. Thomson and Beudant. 

 Diprismatic Iron-Ore, or lievrite. Jamescm. — Diprismatisches Melan-Erz. Mohs. 



Fig. 478. 



Description. Colour black, with a shade of brown or 

 green. Streak black, sometimes inclining to green or brown. 

 It occurs regularly crystallized ; also in masses composed of 

 diverging fibres, and amorphous. Primary form a right rhom- 

 bic prism. Fig. 478. M on M' 112° 37' {Lelievre); 112° 

 {Brooke). Cleavage distinct parallel with the longer diagonal 

 of the prism ; less so parallel with M. Fracture conchoidal 

 and uneven. Lustre semi-metallic. Opaque. Brittle. Hard- 



